lnl: add completions for darwin-rebuild

modules/examples/lnl.nix

@@ -43,9 +43,9 @@
       pkgs.shellcheck
       pkgs.silver-searcher
 
-      pkgs.khd
-      pkgs.kwm
       pkgs.qes
+
+      pkgs.lnl-zsh-completions
     ];
 
   services.khd.enable = true;
@@ -368,12 +368,48 @@
       "darwin=$HOME/.nix-defexpr/darwin"
       "nixpkgs=$HOME/.nix-defexpr/nixpkgs"
       "$HOME/.nix-defexpr/channels"
+      "$HOME/.nix-defexpr"
     ];
 
   nixpkgs.config.allowUnfree = true;
 
-  nixpkgs.config.packageOverrides = super: let self = super.pkgs; in {
-  };
+  nixpkgs.overlays = [
+    (self: super: {
+      lnl-zsh-completions = super.runCommandNoCC "lnl-zsh-completions-0.0.0"
+        { preferLocalBuild = true; }
+        ''
+          mkdir -p $out/share/zsh/site-functions
+
+          cat <<-'EOF' > $out/share/zsh/site-functions/_darwin-rebuild
+          #compdef darwin-rebuild
+          #autoload
+
+          _nix-common-options
+
+          local -a _1st_arguments
+          _1st_arguments=(
+            'switch:Build, activate, and update the current generation'\
+            'build:Build without activating or updating the current generation'\
+            'check:Build and run the activation sanity checks'\
+            'changelog:Show most recent entries in the changelog'\
+          )
+
+          _arguments \
+            '--list-generations[Print a list of all generations in the active profile]'\
+            '--rollback[Roll back to the previous configuration]'\
+            {--switch-generation,-G}'[Activate specified generation]'\
+            '(--profile-name -p)'{--profile-name,-p}'[Profile to use to track current and previous system configurations]:Profile:_nix_profiles'\
+            '1:: :->subcmds' && return 0
+
+          case $state in
+            subcmds)
+              _describe -t commands 'darwin-rebuild subcommands' _1st_arguments
+            ;;
+          esac
+          EOF
+        '';
+    })
+  ];
 
   # TODO: add module for per-user config, etc, ...
   system.activationScripts.extraUserActivation.text = "ln -sfn /etc/per-user/lnl/gitconfig ~/.gitconfig";